2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/54924Starting from the von Neumann equation, we construct the quantum evolution equation for the effective action for systems in mixed states. This allows us to find the hierarchy of equations which describe the time evolution of equal time correlators. The method is applied explicitly to a scalar theory with quartic self-interaction.9 Pages, 1 epsf figureHigh Energy Physics - TheoryHigh Energy Physics - Phenomenologytext